Biological & Soft Matter Seminar: Thermal avalanches: slow sequences of correlated events in disordered media

Abstract:

In amorphous solids, frustrated elastic interactions conspire with thermal noise to trigger anomalously slow yet highly correlated sequences of localized plastic rearrangements, termed "thermal avalanches". Through experiments with crumpled thin sheets under loading, we reveal that these avalanches are scale-free and drive an ever-slowing, logarithmic compaction. Simulations of a mesoscopic model and theoretical arguments show that this slow-down originates from a persistent growth of the lowest effective energy barrier in the system. We study the spatiotemporal structure of avalanches and reveal a hierarchy of fast and slow activation processes. This lays a blueprint for identifying anomalously slow correlations in experiments on a range of disordered systems. In particular, we show that thermal avalanches suggest a physical mechanism for earthquake aftershock sequences and capture previous observations of their temporal correlations.